Data on heavy metal levels (Cd, Co, and Cu) in wheat grains cultured in Dashtestan County, Iran

Due to importance of wheat as the most popular food, in this data article, we determined the accumulation of heavy metal levels including Cd, Co, and Cu in wheat grains in Dashtestan county, Iran. The concentration levels of heavy metals in wheat grains cultured were determined by Flame Atomic Absorption Spectrometry (FAAS).1


a b s t r a c t
Due to importance of wheat as the most popular food, in this data article, we determined the accumulation of heavy metal levels including Cd, Co, and Cu in wheat grains in Dashtestan county, Iran. The concentration levels of heavy metals in wheat grains cultured were determined by Flame Atomic Absorption Spectrometry (FAAS). 1 & Data accessibility Data is with this article.

Value of the data
Data can be used as a base-line data for metal concentration levels in wheat grains. Data shown here can be useful for policy makers, managers, and all related stakeholders, companies, agencies, and institutes working in the fields of food sanitary by imposing proper measures to protect soil from pollutants.
Data shown here may serve as benchmarks for other groups working or studying in the field of toxicology, soils amended with domestic sewage or irrigated with industrial effluents.

Data
The data in Table 1 show that Cd, and Co level were below limit of detection (BLD) in all wheat samples, but the mean concentration levels of Cu was 0.501 with a range of 0.223-0.849 µg/g, and the content level of moisture in wheat samples ranged from 10.15-14.88 (Mean: 11.51%). The measured detection limit values for Cd, Co and Cu were 0.0047, 0.015 and 0.0055 µg/g respectively. Each sample were measured three times and average were reported.

Study area description
Dashtestan County is the biggest county in Bushehr Province, in south west of Iran. This county has the first rank in production of date palm and cereals in Bushehr Province. The capital of the county is Borazjan. In this study, three important regions in wheat production including Shabankareh, Sadabad, and Tang Eram were selected as sampling points (Fig. 1).  Table 1 The content levels of heavy metals (µg/g) and moisture (%) in wheat grain samples.

Sample collection and preparation
Twelve sample were collected in three agricultural areas in Dashtestan county (each site 4 times) just before wheat harvest. Nitrogen fertilizers were used on these grounds. Wheat plants at grain maturity (just before harvest) were randomly chosen within a 5 m×5 m square, were cut with scissors at a height above 10 cm from the soil surface. The wheat samples were air dried for 8 days, and then put into labeled bags and transported to the lab. In the laboratory, grain samples were washed with tap water for 60 min to remove any attached particles, and rinsed three times with distilled water, and oven dried at 38°C till constant weight. Dried samples were ground using a stainless steel grinder (o 0.25 mm) for heavy metal analysis.

Reagents
All the employed oxidants and mineral acids including HNO 3 , H 2 SO 4 , and HClO 4 were of suprapure quality (Merck, Darmstadt, Germany).

Digestion and analytical procedures
A 2 g dried samples were crushed in a mortar and ashed in a muffle furnace at 450 • C for 6 h [1]. If the ashes were not completely white, 2 mL of concentrated HNO 3 were added and the mixture was heated to boiling point on an electric plate heater until the formation of nitrous fumes had stopped [2]. Then, the ashes were returned to the muffle at 450°C for a further 2 h. Finally, the white ashes were digested in a mixture of HNO 3 -HClO 4 -H 2 SO 4 acids (10 ml 70% HClO 4 , 32 ml 10% HNO 3 , and 5 ml 90% H 2 SO 4 ) according to standard analytical procedures [3,4]. A Flame Atomic Absorption Spectrometry (FAAS, Varian AA240, Australia) [5][6][7][8] was used to determine the content levels of Cd, Co, and Cu.